Investigation of Highway Pavement Failure Along Ibadan - Iseyin Road, Oyo State, Nigeria

International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Vol. 1 Issue 8, October - 2012

Investigation Of Highway Pavement Failure Along Ibadan - Iseyin Road, Oyo State, Nigeria

OSUOLALE, O. M.1, OSENI, A. A.2 and SANNI, I. A. 3 Department of Civil Engineering, Ladoke Akintola University of Technology, Ogbomoso.

ABSTRACT of the properties of the soil and its behaviour under load before usage is highly essential in civil The rate of highway failure in Nigeria is alarming engineering and highway pavement construction [1]. and it calls for urgent and decisive action. The causes Failure of highway pavement is a major of the failures had been examined in some States in experience which occurs on Nigeria roads. The Nigeria but there are less records of such study failure of highway pavements is dated back to the around the study area. This research is therefore colonial period [11, 4, 8]. The failures had been aimed at investigating the possible causes of the attributed to some factors, such as properties of highway failure along the study area. construction materials, subgrade conditions, Twenty samples of subgrade and subbase environmental conditions, traffic loading, lack of materials were collected at failed and unfailed drainage and poor workmanship [2, 8, 9, 10]. The sections of Ibadan to Iseyin road. The samples were highway failures are usually defined in terms of the subjected to the following laboratory tests grain size extent of cracking, patching and potholes, surface analysis, Atterberg limit (liquid limit and plastic deformation and surface defects [5]. limit), British standard compaction, West African In recent times, highway pavement failure has standard compaction and California bearing ratio been a very serious problem that cause unnecessary tests. delay in traffic flow, distorts pavement aesthetics, The study revealed that the percentage breakdown of vehicle and most significantly, causes passing sieve No. 200 for the grain size analyses road traffic accident that had resulted into loss of range 17.30 - 32.00% for subgrade and range 19.00 - lives and properties amount to millions of dollars [7, 39.10% for subbase. The liquid limit and plastiIJERTc 10]. Hence there is a lot of concern about the state of index values range 26 - 35% and 9 – 15% disrepair of all categories of roads and the need to respectively for subgrade, while the liquid limit and reappraise the construction materials and method plastic index values for subbase range 26 - 35% and used on roads within the country in order to check 8 - 15% respectively. The values of maximum dry and overcome all the end result of highway density and optimum moisture content range 1.88 - pavement failures already mentioned. 2.12 g/cm3 and 10.15 – 13.2% for subgrade and 1.90 Some studies had been conducted on possible - 2.24 g/cm3 and 9.2 – 14.4% for subbase. The causes of highway failures in Nigeria,especially in California bearings ratio (CBR) values for the Ekiti, Ondo, and some parts of Osun State [7, 8, 10] sample of subgrade range 10 - 29% for 48 hours but there is paucity of research on the geotechnical soaking. The CBR values of subbase range 9% - investigation of the causes of highway failure in oyo 35% for 24 hours soaking. State and especially the Ibadan – Oke Ogun axis. The results therefore show that all the Therefore, this research investigated the possible samples of subgrade and subbase materials conform causes of highway pavement failure along Ibadan – to Federal ministry of works specifications for road Iseyin road, south western Nigeria. works except subbase samples SBF1, SBF3, SBF4 SBF7 and SBF9 and this may be responsible the 2. Description of study area failures. The study area is a 65km road spanning between 1. Introduction Ibadan and Iseyin town. It lies within Moniya in Akinyele local government area of Oyo state to Generally, every work of construction in civil Iseyin in Iseyin local government area of Oyo State. engineering is built on soil or rock and in many The map of the study is shown in Figure 1. instances they are also used as raw materials for Geologically, the study area lies within South construction of infrastructures, such as buildings, western Nigerian basement complex, which forms a earth dams, liners and covers for landfills and part of the Africa crystalline shield. The basement highway pavement. Therefore, a good understanding complex is composed predominantly of folder

www.ijert.org 1 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Vol. 1 Issue 8, October - 2012 gneiss, migmatite, schist and quartzite of precambian 3. Materials and methods age. There exist predominantly two seasons, namely; 3.1Sampling wet and dry season. The wet season starts in Apirl and ends in early October while the dry season starts in late October october and ends in early April. The The method adopted in this project involves study area appears to be well drained during the dry reconnaissance survey of the road to determine the season. The drainage patterns are combination of failed and unfailed sections. The samples of dendrite and radial. The branches of the drainage subgrade and subbase were collected in August patterns discharges into streams and rivers [1]. 2010, the sampling locations comprise Moniya, Idiogin, Idiya, Akowe, Itosi, kambi, Sagbo, Bala, Ekeje and Iseyin as shown in Figure 1.

SCALE: IJERT 5 0 5 10 km

LEGEND

Major road

Minor road

N Failed Location

Unfailed Location W E

S Figure 1: Map of Ibadan - Iseyin road network showing sampling locations

www.ijert.org 2 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Vol. 1 Issue 8, October - 2012 Samples were obtained at the edge of the percentage passing BS sieve No. 200 is less than shoulder of the road, and were dug out using digger 35% except subbase samples SBF7 and SBF9. These and shovel from depth of 300mm for subbase and results are within the requirement of FMW 1200mm for subgrade below the asphaltic surface. specification materials that will be used for road They were suitably packed into sacks and labelled in construction in terms of particles size. In addition, such a manner that each material can be identified since the soil samples contain less fine particles, in distincly. They were transported to the laboratory for the event of rise in water table around the area, the the following tests: Sieve Analysis, Atterberg limit, samples may not be susceptible to swelling. Also, the Compaction and California Bearing Ratio in smaller particles will fill the space between the large accordance with BS 1377 [3]. particles, thereby giving a dense mass of interlocking particles with high shear strength and low 3.2 Test Procedures compressibility.

(a) Particle size distribution. The samples were air 4.2 Atterberg limits dried for about 24 hours and those with cluster particle were pulverised to their natural sizes. 500 The results of the liquid limit (LL), plastic limit gram of each sample was weighed and wet sieve (PL) and plastic index (PI) are presented in tables 1 using 425 µm sieve. Residues of the washed samples and 2. Table 1 shows the liquid limits and plastic were oven-dried and pulverised into fine mass. Each indices for the subgrade soils. The liquid limits and sample was placed in sieve stack and shaken using plastic indices are all below 50% and 30% mechanical shaker. The weight retained in each sieve respectively. They are within the acceptable was recorded for further computations and plotting. requirements for soil sample that can be used as subgrade or fill during construction of highway in (b) Compaction test. The dried soil sample passing Nigeria [6]. These results indicate that the samples the 20mm BS sieve of about 8kg was used. The contain less fine particles such as clay and they have sample was mixed thoroughly with suitable amount less affinity for water and low compressibility. of water of 2.5% intially and later increased to 5%, Therefore, the failures may not be due to infiltration 7.5% and 10% on subsequent tests. The soil was of water into the subgrade layer. The failure may compacted using British Standard and Western therefore be due to some other factors. Table 2 African Standard. The British Standard Method of shows the liquid limits and plastic indices for the compaction test make use of a small mould of subbase samples. The liquid limits and plastic 3 volume 1000cm , small rammer of mass 2.5kg and indices range from 26 to 35% and 8 to 15% the sample is divided into three (3) layers, each layer respectively. The values of the liquid limits are being compacted with 27 blows per layer at a falling within the specification of FMW [6]; LL not greater height of 300mm while the West Africa compaction than 35% but the PIs of some of the samples, SBC, 3 method makes use of big mould of volume 2305cmIJERT, SBF2 and SBF4 were slightly above the FMW a big rammer 4.5kg in mass. The sample is divided specification of not more than 12%. The slight higher into five layers and each layer is compacted with 27 values of PI could account for the failure of the roads blows per layer at a falling height of 450mm [3, 6]. at those sections. A reprehensive sample of the specimen was taken and the moisture content determined. From the graph 4.3 Compaction of the dry density against moisture content, the maximum dry density (MDD) and optimum moisture The results of the maximum dry densities (MDD) content (OMC) were determined. and optimum moisture content (OMC) for the subgrade samples are presented in Table 1. The (c) California bearing ratio (CBR) test. Fresh sets MDD and OMC range from 1.88g/cm3 to 2.12g/cm3 of air-dried samples were compacted in a 152mm and 10,15 to 13.2% respectively. These results are diameter 173mm height CBR mode following similar to the earlier findings of [7, 8, 10]. The MDD already described procedure but at 27 blows per and OMC for the subbase are presented in Table 2. layer. A piece of filter paper was placed on the They range from 1.90g/cm3 to 2.24g/cm3 and 9.2% compacted sample and the base was replaced by a to 14.4%. perforated plate and immersed in water for 48hours. The socked sample was taken to the CBR machine 4.4 California bearing ratio and readings of force were taken at interval of penetration of 0.625mm. The result of California bearing ratio (CBR) test is presented in Tables 1 and 2 for the subgrade 4. Results and Discussion and subbase samples respectively. The CBR for the subgrade range from 10 to 29%, this value shows 4.1 Particle size analysis that the samples are suitable as subgrade because their CBR is greater than 3 to 10%; the specification The results of particle size analyses for the for materials to be used as subgrade [6]. The CBR twenty samples are presented in Figures 2 and 3. The values for the subbase range from 9 to 35 after

www.ijert.org 3 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Vol. 1 Issue 8, October - 2012 soaking for 24 hours. The following samples SBC, of F209 Okitipupa-Igbokoda highway, SBF2, SBF5, SBF6 and SBF8 conform to standard southwestern Nigeria. Ife Journal of having values greater than 30% which is the Science, 2004, 6(1): 41-44. minimum requirement for soaked CBR for subbase [9] Madedor, A.O. Common road maintenance samples. While samples SBF1, SBF3, SBF4, SBF7 problems, causes and possible solutions. and SBF9 are not adequate for subbase having values Engineering focus- A mag. Nig Soc. Eng, less than minimum requirement of 30%. This 1992, 4(4). deficiency in terms of strength could be responsible [10] Ogundipe, O.M. Road pavement failure caused for the failure. by poor soil properties along Aramoko-Ilesa highway, Nigeria. Journal of engineering 5. Conclusions and applied sciences. 2008, 3(3): 239-241. [11] Pollit, H.W.W. Colonial road problems – It can be concluded that the materials used as impressions from visits to Nigeria. HMSO, subgrade are suitable because the values of their London, 1950. geotechnical properties are with the specifications and the road did not fail because of this layer. However, some of the samples used as subbase have the properties below the specification and this is likely to be responsible for the failure.

Reference

[1] Agbede, O.A. and Osuolale, O.M. Geotechnical properties of subgrade soil in Orire Local Government Area. Science focus, 2005; 10(2):137 – 14. [2] Arumala, J.O. and Akpokodje, E.G. Soil properties and pavement performance in the Niger Delta. Q. J. Engng Geol. 1987; 20: 287-296. [3] British Standard Institution. Methods of test for soil for Civil engineering.BS 1377: British Standard Institution, London, 1990. [4] Chukweze, H. Pavement failure caused by soil nd IJERT erosion. Proceedings of 2 International Conference Case. Histories in Geotech Engineering, St Louis, 1988, Paper No, 5:936-937. [5] Federal Highway Authority (FHA). Distress

identification manual for long-term pavement performance program. Office of infrastructural research and development, USA, 2002.

[6] Federal Ministry of Works and Housing. General specifications Roads and Bridges. Federal Highway Department, volume II, pp 145 – 284, 1997. [7] Jegede, G. Effect of soil properties on pavement failures along F209 highway at Ado-Ekiti, southwestern Nigeria, Construction and Building Materials, 2000, 14:311-315. [8] Jegede, G, Highway pavement failure induced by poor geotechnical properties along a section

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Table 1: Summary of Atterberg Limit, Compaction, California bearing ratio tests and Soil Classification Results for subgrade (British Standard)

Sample Liquid Plastic Plastic MDD OMC Soaked AASHTO no limit (%) limit (%) index g/cm3 (%) CBR (%) classification (%) SGC 28 11 15 2.08 13.10 18 A-2-6 SGF1 29 7 13 2.12 10.15 27 A-2-4 SGF2 30 17 13 1.97 13.15 23 A-2-6 SGF3 28 18 9 2.06 11.50 20 A-2-4 SGF4 26 15 11 1.98 10.90 10 A-2-4 SGF5 30 20 10 1.99 11.50 17 A-2-4 SGF6 30 18 13 1.98 11.00 20 A-2-6 SGF7 29 17 13 1.88 14.50 26 A-2-6 SGF8 35 20 15 1.93 11.50 18 A-2-6 SGF9 29 19 10 1.94 13.20 29 A-2-4

Table 2: Summary of Atterberg Limit, Compaction, California bearing ratio tests and Soil Classification Results for subbase (West African Standard)

Sample Liquid Plastic Plastic MDD OMC Soaked AASHTO no limit (%) limit (%) index (%) g/cm3 (%) CBR % classification SBC 27 12 15 1.90 9.20 30 A-2-4 SBF1 35 22 12 2.07 13.60 17 A-2-7 SBF2 34 18 15 2.21 9.60 30 A-2-7 SBF3 30 20 10 2.06 13.10 17 A-2-4 SBF4 34 19 15 2.11 14.40 18 A-2-7 SBF5 30 20 11 IJERT2.17 9.50 35 A-2-4 SBF6 27 18 8 2.24 10.00 31 A-2-4 SBF7 26 15 10 2.01 11.90 18 A-2-4 SBF8 30 20 10 2.06 10.50 31 A-2-4 SBF9 26 18 8 2.21 10.13 9 A-2-4

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100

80 SG (CONTROL) 70 SGF 1 60 SGF 2

50 SGF 3 SGF 4 40 SGF 5 30

SGF 6 Percentage passing (%) passing Percentage 20 SGF 7 10 SGF 8

0 SGF 9 0.01 0.1 1 10

Particle size (mm)

Figure 2: Particle size distribution curve for subgrade samples

100 IJERT 90 SB (CONTROL) 80 SBF 1 70 SBF 2 60 50 SBF 3 40 SBF 4 30 SBF 5 20 SBF 6 percentage passing(%) percentage 10 SBF 7 0 SBF 8 0.01 0.1 1 10 SBF 9 Particle size(mm)

Figure 3: Particle size distribution curve for subbase samples